User's Manual

InfiNet Wireless R5000 Technical User Manual
Copyright © 2004-2006 by InfiNet Wireless Limited.
32
• Specify using “rma bs” command all BS that CPE can potentially work
with
• On each BS that is specified in CPE’s configuration one need to configure
the CPE
Subscriber’s LAN switching from one base station to another takes place with no
LAN Ethernet interface IP-addresses changing.
Router’s configuration rebuilding takes not more than 15 seconds when the base
station changing is performed.
IP-routing is used as a roaming mechanism and this feature allows subscriber’s
relocation within the whole network and switching between different base
stations.
Polling
The WMA/CD (polling) regime is a method of accessing common radio channel
under base station control, which means a centralized distribution of
transmission authorization markers by a base station to subscriber units. This
regime greatly improves operational stability and throughput of base stations
under conditions of heavy load and signal level misbalance between different
subscriber units. It is particularly useful when subscriber units are at long range
from a base station and not in the direct visibility of each other, so that they
cannot avoid mutual collisions in the radio channel by listening each other's
transmission. The polling regime makes it possible to establish reliable
communication between subscribers when the ordinary CSMA/CA wireless access
method does not work at all.
Despite a slight decrease in the maximum transmission speed, the polling regime
substantially increases the total throughput of a base station and provides for its
fair distribution between subscriber units.
Among the drawbacks of wireless polling method one can mention comparatively
greater initial delay and greater response delay variations for series of short
packets, which is adversely affecting such applications as telemetry and on-line
games.
The polling regime is enabled on the base station only. Configuration of
subscriber units needs not to be modified. All those units, however, shall have
RMA protocol enabled.
A base station with polling regime enabled may simultaneously serve both polling
and non-polling subscriber units; presence of non-polling units (dumb units,
relay-points which combine both BS and CPE configuration), however,
substantially reduces the whole system's effectiveness.
To turn polling regime on the BS, type:
rma <IF-NAME> poll
To turn polling regime off, type:
rma <IF-NAME> -poll
Polling mode is recommended to be used with RMA protocol as it
determines the radio environment and makes it predictable. The
competitive results of CSMA/CA and polling protocols are presented
on our web-site
Polling mode can significantly increase a ping round trip time. In this
case this time is not a measure of a link quality.